Effects of octopamine on fluid secretion by isolated salivary glands of a feeding ixodid tick

Thomas L Pannabecker, Glen R. Needham

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Octopamine elicited a dose‐related secretory response by salivary glands isolated from the feeding female tick Amblyomma americanum. Half‐maximal stimulation occurred at about 60 μM. Phentolamine (10 μM) failed to inhibit the octopamine‐mediated response; however, thioridazine (50 μM) inhibited both octopamine (1,000 μM) and dopamine‐stimulated (0.1 μM) secretion. Maximal stimulation by dopamine (1.0 μM) showed no further increase in the rate of secretion after adding octopamine (1,000 or 0.1 μM). Glands responded to octopamine (100 μM) with rates significantly lower than controls following exposure to amphetamine (1,000 μM). Octopamine receptors do not appear to mediate the secretory response, and octopamine may stimulate secretion by releasing catecholamines from presynaptic neurons. These results support the hypothesis that dopamine is the natural transmitter mediating fluid secretion in the feeding tick salivary gland.

Original languageEnglish (US)
Pages (from-to)217-226
Number of pages10
JournalArchives of Insect Biochemistry and Physiology
Volume2
Issue number2
DOIs
StatePublished - 1985
Externally publishedYes

Keywords

  • Amblyomma americanum
  • dopamine
  • octopamine
  • salivary gland
  • tick

ASJC Scopus subject areas

  • Physiology
  • Biochemistry
  • Insect Science

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